Acute coronary syndromes in young patients: Phenotypes, causes and clinical outcomes following percutaneous coronary interventions.

The prevalence of acute coronary syndromes (ACS) among young individuals is increasing, but the phenotypic characteristics, causes and clinical outcomes in this group have not been well described.Between 2009 and 2017, 8712 ACS patients underwent percutaneous coronary intervention (PCI) and were prospectively enrolled. We defined a young patient as female <50 years and male <45 years. The causes of ACS were defined by an adjudication committee. The primary endpoint was the patient-oriented composite endpoint (POCE) of all-cause mortality, myocardial infarction or any revascularization at 12 months.Among 8712 ACS patients, 472 (5.4%) patients were young (26% female). The main cause of ACS in young patients was atherosclerosis (86.5%), followed by coronary artery embolism (9%), and spontaneous coronary artery dissection (SCAD) (4.5%). POCE occurred less frequently in young compared to old patients (8.5% vs. 16.7%, hazard ratio 0.48 (95% confidence interval 0.35-0.66), p < 0.001). The rates of the individual components of the POCE were lower in young including all-cause mortality (3.2% versus 9.5%, 0.32 (0.19-0.54), p < 0.001), myocardial infarction (1.9% versus 3.7%, 0.49 (0.25-0.95), p = 0.035) and any revascularization (5.1% versus 7.4%, 0.65 (0.43-0.97), p = 0.037). Young patients with SCAD had a higher rate of death as compared to those with atherosclerosis, mainly attributed to cardiac deaths.One out of 20 ACS patients undergoing PCI was young and the principal cause was atherosclerosis. Young carry a lower risk for future events compared to older ACS patients. The underlying cause leading to ACS should be considered in appropriate risk stratification of young patients.Clinicaltrials.gov. NCT02241291.